pete
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Post by pete on Jun 26, 2021 15:48:56 GMT 12
Hi guys.
The link to the area reserved for introductions does not seem to work. Allow me to introduce myself in the general chat section. My name is Pieter Albertyn. The name is of Dutch origin; I am an ex-South African.
I have for many years had the desire to restore an old valve radio. I grew up with one in the household and have fond memories of our old Magic-Eye Grundig.
I am 63 years old. I live near Fairlie.
I have limited experience in electrical engineering and electronics. I have a multi-meter and know how to use it. I have a soldering iron and have been known to wield it in anger ! I have built a few kit sets and I am a so-so DIY'er.
In order for me to pick up all of the knowledge and skills to rebuild/restore a valve radio I would have to spend a lot of time and effort, most of which will be wasted, because I do not know what I need to know. (If guess you can figure out what I mean with my last statement !)
I am sure however, that with the help of guys in the know (I am referring to you lot of course !) I will be able to give it a fair go.
My plan is to feed as much info as possible through to this forum. If you guys are then willing to steer me in the right direction, I will do as I'm told and once again feed back all required info. Please advise me on where and how to do this if in fact the idea is feasible.
Regards. Pete. PS: I also do not know how chat rooms, forums etc. work. I plan to figure it out as I go.
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Steve
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Post by Steve on Jun 27, 2021 13:50:58 GMT 12
Hi Pete - I read your whole post, but all I could think was, "You live near the Fairlie Bakehouse and the best pies in the world"... you're a lucky guy! Do you have a radio yet? Or an idea of what kind of radio you'd like to do? I'd avoid Grundig or anything European for a first time around if I was you - most of the stuff like that you find is quite fiddly and complex. Perhaps a WWII era Columbus or similar would be a good starting point, they are generally quite straight forward in terms of technology (comparatively) with large open shallow(ish) chassis' that make them easy to work on. It sounds like you have a good basic setup to get going with, a dim-bulb tester* would be the first thing I'd build to complement your current tooling... any components you need can be easily purchased online as you need them from the likes of Jaycar or SI Components (or as a member of the NZ Vintage Radio Society you can get things through them as well), or anything more specialist like replacement valves can often be sourced through members on here. YouTube will also be quite useful as there are a heap of people doing repair videos. Some of them go into good detail on what they are doing and why, which can be useful when you're just starting out. Lastly, welcome to the community - I look forward to seeing your first set and the progress as you work through it. Cheers, Steve (www.vintageradio.co.nz) * shameless self-promotion
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pete
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Post by pete on Jun 27, 2021 18:35:31 GMT 12
Steve
Thank you for your prompt, and very positive reply.
Yes, Fairlie is indeed famous for the pies. The pie shop also does a mean coffee and my wife and I visit there regularly.
The event which triggered my contact with the NZVRS, was the acquisition of what I considered a suitable radio. (I wanted something which still looked in reasonable condition, was known to have worked not that long ago, and was about of the same vintage as myself ! (I have no idea about the date of manufacture for the radio, but to me it looked about right.)
I hope to attach photos to a post which will hopefully help in the identification of the radio. Along with everything else, I have to learn how forums like yours actually work.
I have had a look at the dim-bulb tester (even before you replied) and I believe that I will be able to construct one with components I have lying around. (One of the advantages of being a hoarder.)
I will also (in my next post, after an attempt at the graphics) list a few things I have noted down to help me structure this project.
Now let's see if I can manage the graphics.
Regards. Pete
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pete
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Post by pete on Jun 27, 2021 18:41:41 GMT 12
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pete
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Post by pete on Jun 27, 2021 18:43:12 GMT 12
More graphics
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pete
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Post by pete on Jun 27, 2021 18:51:52 GMT 12
Things I would like to do: • Identify the radio that I have got (including likely year of manufacture). I can supply photos, dimensions etc. • Determine the original capabilities of the radio • Determine if the radio is worth restoring. • Make the radio safe. • Determine if the radio is still working. • If the radio is not currently working, determine a process by which I can fault-find and analyze. • If the radio proves repairable, determine steps to be taken, find parts etc. • If the receiver can not be restored, determine if the amplifier can be used as a guitar amplifier. If possible , do that. • If the receiver can be restored, do that. • If the receiver and amplifier works, convert the wiring so the radio can also be used as a guitar amplifier. • Convert the radio so it can also receive FM, play MP3s etc. Other things I hope to do: Get to know (at a pen-pal level at least) a few of the guys associated with the NZVRS Learn more about old radios and what makes them tick Get a glimpse into the world of radio restoration and the channels used by those in the know to acquire (and/or restore) parts. I have dealt with JCar and RS before and have heard rumours of "secret" channels out of deep dark Europe ! Cheers for now. Pete.
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Steve
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Post by Steve on Jun 27, 2021 23:04:54 GMT 12
Hi Pete, you're welcome... and yes, the coffee is also pretty darned good there. Ok so you have a 1954 Gulbransen model, with model code 6154 which loosely translates to 6-valve, 1 band (AM / broadcast band) and 19 54 there - made in Wellington by one of the larger NZ radio manufacturers, Collier & Beale, for H. W. Clarke Ltd. So its in the ballpark you wanted, and should be a good easy one to get started with. To answer your wishlist / questions: • Identify the radio that I have got (including likely year of manufacture). I can supply photos, dimensions etc. as above• Determine the original capabilities of the radio AM broadcast band• Determine if the radio is worth restoring. Absolutely• Make the radio safe. Build a dim bulb tester before powering it up, just in case - but first check the power cord (both ends!) for correct wiring, good insulation etc• Determine if the radio is still working. as above• If the radio is not currently working, determine a process by which I can fault-find and analyze. Thats what we do here • If the radio proves repairable, determine steps to be taken, find parts etc. as above• If the receiver can not be restored, determine if the amplifier can be used as a guitar amplifier. If possible , do that. You're unlikely to need to go down this road with this radio by the looks of it• If the receiver can be restored, do that. Yep• If the receiver and amplifier works, convert the wiring so the radio can also be used as a guitar amplifier. A 'gram' input will be a starting point• Convert the radio so it can also receive FM, play MP3s etc. same as the guitar input
The circuit is probably the same as this: nzvrshome.files.wordpress.com/2018/12/cb-model-6153-6v-bc-ac-1953.pdfbut also likely similar to the Byron, which came out a couple of years later but looks similar - nzvrshome.files.wordpress.com/2018/12/cb-model-byron-6v-bc-ac.pdf - this circuit has a gram input, which you could copy(ish) to get started on - you will notice there is a capacitor either side of the volume control in the Byron: this is to keep any high DC voltages (well, any DC voltages full stop) in the radio well away from the external music source (guitar, phone, bluetooth device etc) and so some modification would need to be made, but its minor and not difficult... but before worrying about that, you should make the radio safe, and then operational. You will need to replace the power supply capacitors most likely (unless they have been done recently). There are 2 x 40uF (said: micro-farad) 450V Electrolytic Capacitors (C1 & C2) on the schematic - and there is also a 25uF cap, C3 which is probably in the same can and will also need replaced - 25uF 50V is what I usually use here. This can containing all these caps on your radio is beside the power transformer and branded 'Elna' - and it looks like 47uF 350V is used instead. You should have no trouble finding 47uF 400V or 450V capacitors to replace these though. Its ok to use higher voltage ratings. Once done there, all the tubular paper-foil capacitors (often called wax caps or waxies as they are dipped in wax to protect them from moisture ingress) will need to be replaced - they are likely all crook by now. Having said all this, the best starting point is to remove the chassis from the cabinet and examine what you have - the knobs will need to be removed - probably a small flat-blade grub screw in the side of each knob, then the screws holding the chassis in and unplug the speaker - then it should slide out. Obviously make sure its not plugged in first. It might also be a good idea to take the backshell off the mains plug and check that everything in there is ok too. Do that and post some photos so we can see what you are working with. Cheers, Steve
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pete
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Post by pete on Jun 28, 2021 12:19:30 GMT 12
Steve
Wow, you have got me real exited about this project now. I did not anticipate progress at this pace. The references and info you have provided thus far is of great value to me. I do not intend to simply "get the radio going again". I would love to learn as much as possible, and to treat the radio as a source of information for others as well. If we get the radio going again, it will take pride of place in my "office" (man cave ?) with informative info displayed together with the radio itself.
I am in the process of constructing the dim-bulb tester and hope to have it ready soon.
Before I fire up anything, I have two more questions: * I have read (other sources on the internet) that the chassis of old valve radios need to be connected to the earth wire leading from the mains supply. The radio currently has a 2-core cord leading to the mains. Please advise. * Once I have taken the chassis out of the shell, is it a good idea to try and clean the chassis and components ? I thought a quick sweep with an old paintbrush might be in order ?
Pete
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Steve
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Post by Steve on Jun 28, 2021 12:43:16 GMT 12
Hi Pete - the mains cord looks like a 3-core... its of a type that probably has the earth running down the middle between the phase and neutral wire. I often find this kind of wire is very green (ie: corroded copper) and needs replaced... but inspecting the mains plug and the termination of the earth wire inside the chassis will give you more information here.
A quick sweep with a paintbrush and some compressed air is always useful - do this outside though as you don't know what the dust is or what it contains.
Be careful if you intend to clean the valves - they are lettered with ink that will easily wipe off, leaving you with no easy way to identify them. Note where each comes from if/when you remove them - I will typically write the code on the valve if its already wiped off.
And finally, I really like it when people restore a radio and keep a folder with photos and information relating to the restoration that goes with the radio... Its also nice to get its previous history where possible. I have a couple of sets which I can trace back to the original owners and homes they were first in. Its rare to be able to do that, but nice if you can.
Cheers, Steve
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pete
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Post by pete on Jun 28, 2021 16:01:45 GMT 12
Steve
Progress report 1:
The dim bulb tester has been completed. I used components at hand. Had to buy in an incandescent bulb from my FourSquare. (I banned all incandescents from my house when we built in 2016.) The filament on this bulb is not visible and I am not sure if it will be usable. See photo. I think it may just do the job. I should be able to gauge the "glow" of the filament from the light being emitted. I have removed the chassis from the cabinet. No problems in doing so. See photos.
Feed-back:
I see no apparent physical damage to the chassis or any of the components. There are no missing parts either (that I know of). There is a slightly suspect dark spot underneath and in the centre of the chassis (see photo 9).
I see no evidence of repairs (professional or otherwise) which might previously have been done.
The chassis and components are dirty but not soiled. No visible rust or spillage from leaking components.
Quality of original workmanship is not as good as I have seen on German radios of the same era. (Maybe I have forgotten what the Grundig really looked like. From memory the lay-out and soldering on the Grundig was somewhat neater ?)
The speaker is not torn or damaged. Seems to be in perfect order.
Questions:
Why are there three (3) electrical wires leading to the speaker ? I have thus far attached a few photos at a time to a post, each such post set up for the purpose of showing graphics only. Is this advisable ? I compress photos to about 240KB each. Does the resolution and number of colours leave you with enough detail for your purposes ? Please advise if any of the photos need to be re-taken due to lighting, contrast or other problems. I can also produce photos of details you have a special interest in. I can do macro's (limited focal distance but I can make a plan) if/when required. Is there some why by which I can "document" this thread by printing to PDF (maybe even printing on paper and then scanning ?) so I can digitally store the content of the thread ? I foresee instances where I will have to refer to details contained in the thread, while not being on-line.
Photos in next few posts.
Regards Pete
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pete
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Post by pete on Jun 28, 2021 16:03:56 GMT 12
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pete
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Post by pete on Jun 28, 2021 16:04:58 GMT 12
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Steve
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Post by Steve on Jun 28, 2021 17:27:36 GMT 12
Hi Pete - regarding photos - don't reduce the colour depth, it makes it hard to see detail when zoomed in. You should be able to just resize them to around 1800-2000px wide by whatever maintains the aspect ratio in height and still be under the attachment size cap. And I just attach as many photos to every post as I can - but there are no rules about that, do what works best for you. What you've done so far seems fine to me.
regarding offline documentation - Microsoft Word? Google Docs with offline mode? Even just WordPad (built in to Windows) would probably do.
The chassis looks reasonably original... although the power supply filter electrolytic can looks as if it might be a replacement. I'm not really a Collier & Beale guy so I don't know if those Solar caps are likely original or replacements. And the three wires to the speaker will be two for the output transformer (mounted on top of the speaker) and probably an earth wire to the frame or a shield on the output transformer.
I think the next step will be to draw out the power supply section and make sure you understand how it is configured before attempting to replace any parts. There are several ways to replace the electrolytics from just whacking them in, to fully restuffing the existing can with new parts. I tend to take a middle-ground approach and use tag-strip to mount new caps and then fit that near the existing can underneath.
Cheers, Steve
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pete
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Post by pete on Jun 28, 2021 19:42:01 GMT 12
Steve
Thanks for all of the feed-back.
I do not have an ideal work space for jobs like this one, right now. I thus have to re-arrange and juggle other half-finished projects to make space for work on the radio. This also means that I have to wait for decent weather conditions each time before I tackle the next job. Luckily I got a few things done over the weekend and earlier today. Right now the weather is a bit dodgy and I may thus only make progress in a day or two. I intend to look into that power cable (number of wires and general condition) and try to do a bit of a clean-up of the chassis as well as the cabinet. The cabinet is in pretty good shape - I intend to just wipe it clean with a damp cloth and put some furniture polish on it. The timber is awfully dry and I am afraid that it may crack once the radio is being used again. I may even treat the inside with a suitable timber preservative before I re-assemble the radio. (Any ideas on this ?) The speaker cloth (is that what you call it ?) is in decent shape and I do not intend to replace it.
Once I have done a bit of a clean-up I will concentrate on an analysis of the power supply. I will then report back with diagrams, photos or both.
One thing I can do (even in the worst of weather conditions) is to look into ways of preserving the thread and documenting of the process.
Cheers. Pete
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Steve
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Post by Steve on Jun 29, 2021 8:29:51 GMT 12
Hi Pete, in regards to the cabinet I have a preferred method, but so does everyone else... But first, a disclaimer - I'm not a cabinet specialist, nor a refinishing specialist - I just know what I know (or, at least, what I think I know). I'm sure holy wars get started over this topic, but personally I let the cabinet decide which way I go. If its in good shape, like yours, I would clean it and then furniture wax it (I use Briwax, often a tinted version) - not polish, as these tend to contain silicone. The problems with silicone are not immediately apparent as they make the radio look fantastic in the short term, but if you ever want to strip and refinish it using traditional lacquers then you'll run into huge problems with the lacquer 'fish-eye'ing.
And definitely preserve the original grill cloth if you can - Sometimes this will be attached to the baffle board the speaker is screwed to, and can be carefully removed and stored while the cabinet is being worked on - other times you'll find the cloth glued to the cabinet itself, so you need to carefully work around it.
Also, get some stiff card to tape/screw across the front of the speaker while its out - speakers will find every sharp object on your bench and throw themselves on them. Its a thing, protect the speaker from itself.
If you need new power cord I have some period-correct triple-flex here but from what I could see yours looked ok at the radio end.
Cheers, Steve
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